The maneuverability of an aircraft depends heavily on the movement of hinged sections or flaps located at the trailing edges of the wings. By selectively extending and retracting the flaps, the aerodynamic flow conditions of the wings may be influenced so as to increase or decrease the lift generated by the wings. For example, during the take-off and landing phases of a flight, the position of the flaps of the aircraft are adjusted to optimize the lift and drag characteristics of the wing. It can be appreciated the reliable operation of the flaps is of critical importance to an aircraft.
In large aircraft, a series of flaps are provided on the trailing edge of each wing. The flaps are raised and lowered in a conventional manner by a hydraulically actuated linkage of bell cranks, pushrods, and idlers. A flap control lever is provided in the cockpit of the aircraft to control the system mechanically. The flap control lever is connected by conventional and teleflex cables to a hydraulic actuating mechanism. As is known, these hydraulic actuating mechanisms utilize large centralized pumps to maintain pressure hydraulic pressure within the system. Hydraulic lines distribute the hydraulic fluid under pressure to corresponding flap actuators. In order to insure the reliability of the system, multiple hydraulic lines are run to each flap actuator.
While functional for their intended purposes, these prior hydraulic systems have certain inherent problems. For example, it is highly desirable for all systems on an aircraft to be easily serviceable so that departure of the aircraft will not be delayed while mechanics attempt to diagnose and repair the aircraft. However, given the complexity of the pumps and the lines in the hydraulic system of the aircraft, it is often relatively difficult and costly to diagnose and/or repair the hydraulic system. Further, the use of multiple hydraulic lines must be run to each flap actuator to ensure redundancy in the system is costly, both in terms of weight and money. Hence, it is highly desirable to provide a redundant, flap actuator control system that is simple to install and service and this is lightweight.
Therefore, it is a primary object and feature of the present invention to provide a flap actuator that is simple to install and service.
It is a further object and feature of the present invention to provide a flap actuator that incorporates redundant load path design.
It is a still further object and feature of the present invention to provide a flap actuator that maintains the position of a flap of an aircraft in response to a compression load thereon by the flap.
In accordance with the present invention, a flap actuator is provided for controlling movement of a flap on a wing of an aircraft. The flap actuator includes a shaft extending along a longitudinal axis and having a terminal end operatively connectable to the flap. The shaft is movable between a first retracted position and a second extended position. A no-back assembly is operatively connectable to the shaft. The no-back assembly prevents movement of the shaft toward the retracted position in response to a compressive force generated by the flap.
The no-back assembly includes a housing for supporting the shaft and a first gimbal for interconnecting the housing to the wing. A second gimbal also interconnects the housing to the wing. First and second pins extend between the housing and the first gimbal, and interconnect the second gimbal to the first gimbal and the housing. A mounting pin extends through the first gimbal and is operatively connectable to the wing.
The flap actuator also includes a ball nut engageable with the shaft and rotatable about the longitudinal axis. Rotation of the ball nut in a first direction causes the shaft to move toward the extended position, while rotation of the ball nut in a second direction causes the shaft to move toward the retracted position. The shaft includes a hollow ball screw extending along the longitudinal axis and an inner bar extending through the ball screw. A motor having a rotatable drive shaft is also provided. The drive shaft is rotatable in first and second opposite directions. A gear assembly translates rotation of the drive shaft to the ball nut. The gear assembly includes a clutch. The clutch disengages the drive shaft from the ball nut in response to a predetermined force thereon.
In accordance with a further aspect of the present invention, a flap actuator is provided for controlling movement of a flap on a wing of an aircraft. The flap actuator includes a housing having a leading end and a trailing end. A ball nut is rotatably supported in the housing. A ball screw extends along a longitudinal axis and has a terminal end operatively connectable to the flap. The ball screw movable between a first retracted position and a second extended position in response to rotation of the ball nut. A one-way roller clutch is operatively connectable to the ball nut. The roller clutch engages the housing and prevents rotation of the ball nut in a first direction in response to a compressive force on the ball screw by the flap. A gimbal assembly is connected to the housing and is connectable to the wing.
The gimbal assembly includes a first gimbal for interconnecting the housing to the wing and a second gimbal for interconnecting the housing to the wing. First and second pins extending between the housing and the first gimbal. In addition, the first and second pins interconnect the second gimbal to the first gimbal and the housing. The gimbal assembly also includes a mounting pin extending through the first gimbal and being operatively connectable to the wing.
Rotation of the ball nut in a first direction causes the ball screw to move toward the extended position. Rotation of the ball nut in a second direction causes the ball screw to move toward the retracted position. A motor having a rotatable drive shaft is provided. The drive shaft is rotatable in first and second opposite directions. A gear assembly translates rotation of the drive shaft to the ball nut. The gear assembly includes a clutch that disengages the drive shaft from the ball nut in response to a predetermined force thereon. An inner bar extends through the ball screw.
In accordance with a still further aspect of the present invention, a flap actuator is provided for controlling movement of a flap on a wing of an aircraft. The flap actuator includes a housing having a leading end and a trailing end. A ball nut is rotatably supported in the housing. A motor has a rotatable drive shaft that is rotatable in first and second opposite directions. A gear assembly translates rotation of the drive shaft to the ball nut. A ball screw extends along a longitudinal axis and has a terminal end operatively connectable to the flap. The ball screw is movable between a first retracted in response to rotation of the ball nut in a first direction and a second extended position in response to rotation of the ball nut in a second direction. A one-way roller clutch is operatively connectable to the ball nut. The roller clutch engages the housing and prevents rotation of the ball nut in a first direction in response to a compressive force on the ball screw by the flap. First and second concentric gimbals are positioned about the longitudinal axis adjacent the housing. A first pin extends through the first and second gimbals and being operatively connected to the housing.
A second pin may also extend through the first and second gimbals and being operatively connected to the housing and a mounting arrangement is provided for interconnecting the first gimbal to the wing. It is contemplated for the first and second gimbals to have a generally rectangular configuration.